Related Topics

Illustrations

In-Depth From A.D.A.M. Background

Back pain is one of the most common reasons people visit their doctor. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, 8 out of 10 people have some type of backache.

Back pain can be acute, subacute, or chronic.

Acute back pain develops suddenly and lasts up to several weeks. Acute pain is the most common type of back pain.

Subacute back pain is pain that lasts up to 3 months.

Chronic back pain can begin abruptly or gradually, but it lasts longer than 3 months.

Back pain can occur in any area of the back, but it is more common in the lower back, which supports most of the body's weight.

The Spine

The back is highly complex, and pain may result from damage or injury to any of its various bones, nerves, muscles, ligaments, and other structures. Still, despite sophisticated techniques, which provide detailed anatomical images of the spine and other tissues, the cause of most cases of back pain remains unknown.

Vertebrae. The spine is a column of small bones, or vertebrae, that support the entire upper body. The column is grouped into three sections:

The cervical (C) vertebrae are the seven spinal bones that support the neck.

The thoracic (T) vertebrae are the twelve spinal bones that connect to the rib cage.

The lumbar (L) vertebrae are the five lowest and largest bones of the spinal column. Most of the body's weight and stress falls on the lumbar vertebrae.

Each vertebra is designated by using a letter and number, allowing the doctor to determine where it is in the spine.

The letter reflects the spinal region where the vertebra is located:

C=cervical (neck region)

T= thoracic (chest, or middle back, region)

L=lumbar (lower back)

The number signifies the vertebra's place within that spinal region. The numbers start with 1 at the top of a region and count up as the vertebrae descend within the region. For example, C4 is the fourth bone down in the cervical region, and T8 is the eighth thoracic vertebrae.

The Disks. Vertebrae in the spinal column are separated from each other by small cushions of cartilage known as intervertebral disks. The disks have no blood supply of their own. They rely on nearby blood vessels to keep them nourished.

Processes. Each vertebra in the spine has a number of bony projections called processes. The spinous and transverse processes attach to the muscles in the back and act like little levers, allowing the spine to twist or bend. The particular processes form the joints between the vertebrae themselves, meeting together and interlocking at the zygapophysial joints (more commonly known as facet, or z-joints).

Spinal Canal. Each vertebra and its processes surround and protect an arch-shaped central opening. These arches, aligned to run down the spine, form the spinal canal, which encloses the spinal cord.

Spinal Cord. The spinal cord is the central trunk of nerves that connects the brain with the rest of the body. Each nerve root passes from the spinal column to other parts of the body through small openings, bounded on one side by the disk and on the other by the facets. When the spinal cord reaches the lumbar region, it splits into four bundled strands of nerve roots called the cauda equina (meaning horsetail in Latin).

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).